1. Field of the Invention
An embodiment of the present invention relates to a fabrication method of a secondary battery.
2. Description of the Related Art
In general, batteries may be largely classified into primary batteries and secondary batteries. The primary batteries are mostly cylindrical batteries, and the secondary batteries are classified into prismatic batteries and cylindrical batteries. The prismatic battery employs a metal can or a pouch as a sheath member, and a battery employing a pouch sheath member is called a “pouch-type” battery.
The prismatic battery is generally manufactured by fabricating a wound or stacked electrode assembly including a negative electrode plate, a separator and a positive electrode plate, accommodating the electrode assembly in a prismatic can or pouch, and injecting an electrolyte into the prismatic can or pouch.
Meanwhile, the wound electrode assembly is fabricated by stacking a negative electrode plate, a separator and a positive electrode plate, shaped of strips, and winding a stacked structure substantially in a jelly-roll configuration, demonstrating excellent productivity. However, since curved portions are formed at opposite sides due to the winding, concentrated stress may be applied to the curved portions, resulting in fracture of an electrode plate or separation of an active material. In addition, since the electrode assembly is wound, electrolyte impregnation passages are limited, thereby deteriorating an electrolyte impregnating characteristic.
In addition, since the stacked electrode assembly is fabricated by stacking a plurality of plates in the order of a negative electrode plate, a separator and a positive electrode plate, no curved portions are generated in the stacked electrode assembly, so that problems, such as fracture of an electrode plate or separation of an active material, may not be caused. However, when stacking is separately performed in the order of a separator, a negative electrode plate, a separator and a positive electrode plate, time required for manufacturing the electrode assembly may be increased.